The definition of code switching is the switching between elements of two or more languages by speakers in a bilingual situation. Personally, I think that it is useful to think about code switching even in monolingual situations where there are distinct registers (formal and informal) or dialects.
However, neither under the narrow or the broad definition of code switching, this would qualify. This sounds more like the case of borrowing. This is something imported into the language and used by speakers who (presumably) do not switch between two codes but rather have enriched the one code they use.
On the other hand, I can imagine a situation where using the English spelling out could become a part of a sociolect - for instance, some people using it to indicate belonging to a modern or better off group - in which case, code switching could be a useful model for thinking about its use. But it would always be a borderline case.